Question

People get bored. To ease this, they started a competition for cookies: hit the tape with the block and get a cookie. I put a piece of tape on the floor 1.5 m from the edge of the table. On the edge of the table, I put a curved ramp (stolen from a Hot Wheels set). I set a small block (m=0.29kg) at the bottom. A larger block (mass 2m) is placed at some height above the table along the ramp and allowed to slide down the ramp and hit the smaller block, launching it horizontally off the table. If the table is 95 cm off the floor, how high off the table (in meters) must the large block start for the small block to hit the tape mark? [Assume the collision is elastic and neglect all friction.]

Answer 1

see the diagram :

first we find , velocity of m when it leaves the table along horizontal direction.

time taken by m to reach ground is t =

in this time the m covers 1.5 m along horizontal, .

the velocity of 2m before it hits the m is, u = .

As the collision is perfectly eleastic :

velocity of second body after collision is given by :

[u1 = velocity of first body before collision, u2 = velocity of second body before collision, v1 = velocity of first body after collision, v2= velocity of second body after collision]

[since u2 = 0]

[answer]